Promising Findings for SCC in Organ Transplant Recipients Repeated PDT Treatments May Reduce the Incidence of Sccs in This High-Risk Population
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Oncology Watch Cyclic Photodynamic Therapy: Promising Findings for SCC in Organ Transplant Recipients Repeated PDT treatments may reduce the incidence of SCCs in this high-risk population. By Jonathan Wolfe, MD hotodynamic therapy with 5-aminolevulinic acid SOTRs typically undergo chemoprophylaxis with sys- (ALA, Levulan, DUSA Pharmaceuticals) has temic retinoids, although there have been few ran- become established as a safe and effective option domized controlled trials to quantify their benefit. Pfor the management of AKs (see the January edi- Acitretin is probably the most frequently used agent,3 tion, available at PracticalDermatology.com). The drug but isotretinoin and etretinate are also used, and there is indicated, along with blue light application, for the is anecdotal evidence to support the use of treatment of minimally to moderately thick actinic bexarotene.4 Of note, rebound flares have been associ- keratoses of the face or scalp. However, there has ated with discontinuation of retinoids, leading some to been increasing interest in the role of PDT to manage advocate chemoprevention as a lifelong therapy.3 other types of skin cancers. A recent study shows that the procedure may be effective for reducing the inci- An Emerging Option dence of squamous cell carcinoma (SCC) in solid Given the concerns about high rates of NMSCs in organ transplant recipients (SOTR). transplant recipients, there is interest in identifying optimal treatment and prevention strategies. While Skin Cancer and SOTRs retinoid chemoprophylaxis is an important and effec- Compared to the general population, solid organ trans- tive option, additional interventions are welcome. plant recipients are at higher risk of skin cancer, with Recent findings suggest a role for cyclic 5-ALA PDT up to a 100-fold estimated increase in the relative risk therapy.5 Twelve high-risk SOTRs received cyclic PDT of squamous cell carcinoma (SCC) compared to the treatments at four- to eight-week intervals for two non-transplanted population. The risk for basal cell years. New SCCs were counted during the year before carcinoma is increased about 10- to 16-fold in SOTRs.1 initiation of therapy and again at 12 and 24 months A recent retrospective cohort study of 1,476 renal following the first PDT treatment. Researchers calcu- transplant and 458 heart transplant recipients found lated median reductions in SCCs of 79 percent and 95 that 200 patients developed a first non-melanoma skin percent, respectively, from the pre-treatment counts. cancer (MNSC) after a median follow-up of 6.8 years PDT treatments were well tolerated. The authors of after transplantation (three-year risk of primary NMSC the current study urge larger studies of PDT for pre- was 2.1 percent). Of the patients with a primary vention of SCCs in SOTRs. NMSC, 91 (45.5 percent) had a second NMSC after a An earlier study had shown promise for ALA PDT median follow-up 1.4 years. The three-year risk of a for the treatment of AKs and Bowen’s disease in trans- second NMSC was 32.2 percent—49 times higher than plant recipients.6 That study compared the response to for patients with no previous NMSC.2 either one or two courses of ALA PDT in 20 transplant In light of this known increased risk for NMSC, recipients and 20 controls. Cure rates in both groups 14 | Practical Dermatology | October 2010 .